pops and power?

[volospian]

My cerb snaps, crackles and pops like a famous kellogs breakfast cereal through a 10kilowatt amp.

Now, admittedly, every time it does it (mainly around 3500rpm, and again around 2500rpm, with random barks and spits now and again, like the poor thing has exhaust pipe tourettes) I laugh like a schoolkid, but I can't help wondering if I'm paying for the comedy value of all those terrified old biddies with a drop on power.

So, do the rice krispies mean a poor map and a reduction of power, or is there little in it and I should just carry on giggling like Homer Simpson every time the AJP demon spits its distaste at a tree hugging cyclist?

[Mars]

A properly mapped car won't pop and bang like a standard Cerb does. It might "blow off" on the overrun from high speeds but maybe only once - definitely not consistently like Cerbs tend to.

However, whether you're trading power for fireworks depends on where they are present - what engine speed/loads cause them? If they happen following a "foot to the floor" moment, then the answer is probably yes. Any pops and bangs are the result of the map being too rich. If this happens in the "power" section of the map then you are likely to be trading noise for power.

Regardless of *where* you get the noise, it is almost certain that you are trading noise for economy.


I'd be interested in opinions of the owners who have had remaps, whether their cars are less vocal than before. Mine had an Emerald and was perfectly mannered - although still as loud as God.

[jammy_basturd]

Mars said:

However, whether you're trading power for fireworks depends on where they are present - what engine speed/loads cause them? If they happen following a "foot to the floor" moment, then the answer is probably yes. Any pops and bangs are the result of the map being too rich.

Not neccesarily. If the overlap (exhaust valve opening as the inlet valve is closing) on the cam is enough, then you'll get unburnt fueling just passing straight from the inlet, into the combustion chamber and straight into the exhaust where it'll ignite.

[JensenA]

It's actually a WEAK mixture that will increase the pops n bangs, which are one of the characteristics of a flat plane crank engine. Mine is a remapped 406hp, and it pops n bangs on the overun. Thts one of the things I love about the AJP, it makes it unique. You shouldn't be trying to get it to pop and bang, just hav the engine set up correctly, and it just does !

Edited by JensenA on Wednesday 2nd July 10:05

[markh1]

Mine has had a re-map prior to any mods. After the remap it still popped and banged. It now has ACT free flow manifolds and decats and it pops and bangs constantly. I would quite like to get it re-mapped again.

[jammy_basturd]

I was surprised to read on here the other day that a weak mixture will help the snap, crackle and pop! I guess a weak mixture makes the engine run hotter, the exhaust gets hot, which then helps to ignite and unburnt fuel in the exhaust system...

[Mars]

jammy_basturd said:

Mars said:

However, whether you're trading power for fireworks depends on where they are present - what engine speed/loads cause them? If they happen following a "foot to the floor" moment, then the answer is probably yes. Any pops and bangs are the result of the map being too rich.

Not neccesarily. If the overlap (exhaust valve opening as the inlet valve is closing) on the cam is enough, then you'll get unburnt fueling just passing straight from the inlet, into the combustion chamber and straight into the exhaust where it'll ignite.

It's a single overhead-per-bank cam so overlap is fixed. If one car pops and bangs more than another, the overlap can't be to blame.

[Steve_T]

The car is mapped using different sites maximum power(torque) with a wide open throttle and overrun where the throttle is closed/slightly open, so IMHO no, the two are not related. HTH.

Steve.

Edited by Steve_T on Wednesday 2nd July 15:55